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Published on: 2/25/2026
Gut changes are common and often not cancer, but red flags like blood in the stool, bowel habit changes lasting more than 2 to 3 weeks, unexplained weight loss or fatigue, and persistent abdominal pain warrant prompt medical evaluation, and screening from age 45 can prevent cancer by finding and removing polyps.
There are several factors to consider, including benign causes, personal and family risk, and which tests to do next such as stool tests and colonoscopy; see below for the complete guidance and actionable next steps that may affect your care.
Changes in your gut can be unsettling. Maybe your bowel habits have shifted. Maybe there's blood in your stool. Or perhaps you feel ongoing abdominal discomfort that just isn't going away.
It's natural to wonder: Is this colorectal cancer?
Colorectal cancer (also called colon cancer or rectal cancer) is one of the most common cancers worldwide. The good news is that when caught early, it is highly treatable. Many gut changes are caused by less serious conditions — but some symptoms should never be ignored.
Let's walk through what colorectal cancer is, what symptoms to watch for, why your gut may be changing, and what medical steps to take next.
Colorectal cancer begins in the colon or rectum, which are parts of the large intestine. Most cases start as small, noncancerous growths called polyps. Over time — often years — some polyps can turn into cancer.
This slow development is why screening is so powerful. Detecting and removing polyps early can prevent colorectal cancer entirely.
In early stages, colorectal cancer may not cause symptoms. That's why screening is so important.
When symptoms do appear, they may include:
It's important to understand that these symptoms do not automatically mean colorectal cancer. Conditions like hemorrhoids, irritable bowel syndrome (IBS), infections, inflammatory bowel disease (IBD), and diverticulosis can cause similar symptoms.
However, persistent or worsening symptoms deserve medical evaluation.
Not every bowel change is cancer. In fact, most are not. Common reasons for gut changes include:
Stress can alter gut motility and trigger constipation or diarrhea.
Antibiotics, iron supplements, pain medications, and some antidepressants can affect bowel habits.
Bacterial or viral infections can temporarily disrupt digestion.
Still, if symptoms are new, persistent (more than a few weeks), or worsening, colorectal cancer must be ruled out.
Anyone can develop colorectal cancer, but risk increases with:
If you have a first-degree relative (parent, sibling, child) with colorectal cancer, your risk is significantly higher.
You should seek medical evaluation promptly if you experience:
These do not guarantee colorectal cancer — but they require proper testing.
If colorectal cancer is suspected, your doctor may recommend:
They will ask about:
These can check for hidden (occult) blood in the stool.
To look for:
This is the most important diagnostic tool. A flexible camera examines the colon and rectum. During the procedure:
If colorectal cancer is found, early detection dramatically improves survival rates.
Most medical organizations recommend regular colorectal cancer screening starting at age 45 for average-risk adults.
Screening options include:
If you have higher risk factors, screening may begin earlier.
Hearing a cancer diagnosis is frightening. But it's important to understand:
The stage at diagnosis makes a major difference — which is why early evaluation matters.
If you're concerned about your symptoms and want to better understand whether they could be related to something serious, use this free Colon Cancer symptom checker to get a personalized assessment in minutes based on your specific symptoms.
This is not a diagnosis, but it can help you decide how urgently to seek care.
While not all cases are preventable, you can lower your risk by:
Lifestyle changes not only reduce colorectal cancer risk but also improve overall gut health.
It's important not to panic over every digestive change. Our gut naturally fluctuates due to diet, stress, and normal biological variation.
But it's equally important not to ignore persistent warning signs.
Colorectal cancer often develops silently. When symptoms appear, they deserve attention.
If something feels different from your normal baseline — especially if it persists — trust that instinct and get it checked.
Gut changes are common. Most are caused by noncancerous conditions. However, colorectal cancer is common enough that ongoing or concerning symptoms must be evaluated.
Do not self-diagnose. Do not ignore persistent bleeding or bowel changes. And do not delay screening if you are 45 or older.
If you are experiencing:
Speak to a doctor promptly. Some causes may be minor. Others, including colorectal cancer, can be life-threatening if ignored.
Early detection saves lives. If something doesn't feel right, take the next step today.
(References)
* Maida, C. M., Sferrazzo, S., Alaimo, B., Scalia, G., Alaimo, I., Bellanca, L., Cannova, S., Alaimo, G., & D'Alessandro, R. (2021). Change in bowel habit and rectal bleeding as red flags for colorectal cancer: a systematic review. *Journal of Clinical Medicine*, *10*(14), 3097.
* Dekker, E., Tanis, P. J., Vleugels, J. L. A., Kasi, P. M., & Wallace, M. B. (2023). Diagnosis and Management of Colorectal Cancer: An Updated Review. *JAMA*, *329*(3), 251–263.
* US Preventive Services Task Force, Davidson, K. W., Barry, M. J., Mangione, C. M., Cabana, L. S., Caughey, A. B., ... & Wong, J. B. (2021). Colorectal Cancer Screening: Updated Recommendations From the U.S. Preventive Services Task Force. *JAMA*, *325*(19), 1965–1975.
* Rawla, P., Sunkara, T., & Barsouk, A. (2022). Colorectal Cancer: Epidemiology, Risk Factors, and Clinical Presentation. *Medical Sciences (Basel, Switzerland)*, *10*(4), 184.
* Zhang, M., Ye, Y., Ma, K., Wang, Y., Zhang, W., Chen, S., Sun, Y., & Chen, G. (2023). New advances in the diagnosis of colorectal cancer. *Frontiers in Oncology*, *12*, 1074092.
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